1. Field
This application relates generally to a system for trimming leafy vegetables of varying size and shape and, more specifically, to an image-guided, servo-controlled water knife that tops and tails romaine lettuce heads.
2. Description of the Related Art
In commercial harvesting operations, leafy vegetables (e.g., heads of romaine lettuce) are cut from a plant root and are processed to remove undesirable portions of the vegetable. Commercially harvested heads of romaine lettuce have a tail or core end that includes the lettuce stem where the head was previously attached to the plant root. The lettuce head also has a top or leafy end opposite the core end. Lettuce heads are typically trimmed manually to remove portions of the top and tail of the lettuce head. A worker manually removes the core using a knife or hand tool. The worker also trims the tips of the leaves from the top end of the head that may have been damaged by the sun or the harvesting process.
This manual trimming process, sometimes called topping and tailing, can be performed in the field immediately after harvesting. A trained worker can top and tail each head of lettuce so that only the undesirable portions are removed, minimizing wasted product. However, manual topping and tailing is time consuming and may be performed outdoors where the worker is subjected to sun and heat. Additionally, cut portions of the lettuce head may discolor or brown if the juices of the plant are not immediately rinsed after cutting with a knife.
Some commercial harvesting operations have automated the topping and tailing process using two or more cutting blades spaced a fixed distance apart. In such systems, mechanically-actuated blades slice the top and tail end of the romaine lettuce as the vegetables are conveyed through the machine. In some cases, a fixed-blade system may be faster than manual trimming. However, the size and shape of each lettuce head varies and fixed-blade systems lack the flexibility to trim each head so as to minimize wasted product. In order to process a variety of head sizes, the blades may be set at a narrow spacing so that the smallest anticipated head size is trimmed by both cutting blades. However, when larger lettuce heads are processed using the narrow blade spacing, a significant amount of usable vegetable is removed, wasting usable lettuce product. Additionally, some systems may waste product by making cuts that are unable to conform to the rounded contour of a lettuce head. For example, in some systems a blade may be set to remove the tips of shorter, outer leaves, but will also remove usable portions of the longer, inner lettuce leaves.
In some aspects of the system, the lower feed conveyor is configured to convey the lettuce head under the tail-cutting mechanism as the second cutting nozzle is articulated through the tail-cutting arc to produce a v-notch cut in the tail end of the lettuce head.